Conventionally, a card reader structured to read magnetic data on a card and/or record magnetic data on a card has been widely utilized. In an industry of the financial institutions where the card reader is utilized, a so-called skimming has conventionally become a serious problem in which a criminal attaches a magnetic head to a card insertion part of the card reader to illegally acquire magnetic data of a card by using the magnetic head. In order to prevent this problem, a card reader has been proposed which is provided with a disturbing magnetic field generator for preventing reading of magnetic data by using a magnetic head for skimming (hereinafter, referred to as a “skimming magnetic head” (see, for example, Patent Literature 1).
In the card reader described in Patent Literature 1, at the time of card insertion when a card is to be inserted into the card reader, a disturbing magnetic field generator is driven for a predetermined time period to generate a disturbance magnetic field. Therefore, even when a skimming magnetic head is attached to a card insertion part, it is possible that illegal acquisition of magnetic data is prevented by preventing appropriate reading of magnetic data through the skimming magnetic head.
The card reader described in Patent Literature 1 is provided with a disturbance magnetic field generator and thus, as described above, reading of magnetic data by a skimming magnetic head can be prevented. However, in the card reader, the magnetic field generated by the disturbing magnetic field generator may affect reading of magnetic data by a magnetic head for data reading which is arranged in an inside of the card reader. In order to reduce the problem, it is conceivable that the disturbing magnetic field generated by the disturbing magnetic field generator is reduced, or that generation of the disturbing magnetic field is stopped at the time of reading of magnetic data by the magnetic head for data reading. However, according to these measures, it may be difficult to prevent reading of magnetic data by a skimming magnetic head.